This section is intended to provide relevant background information to facilitate a better understanding of the various aspects of the described embodiments. Accordingly, it should be understood that these statements are to be read in this light and not as admissions of prior art.
In oilfield exploration and production operations, oil and gas wells are drilled in sections. The initial section of the well starts at the ground level, or in the case of offshore wells, at the seabed, and is drilled a relatively short distance due to the unconsolidated nature of soil/formation at the surface. The first well section is drilled and isolated by lowering and, in some cases, cementing in place an initial string of conductor pipe in the drilled hole. Once the initial string is drilled and isolated, the next section of the well is drilled out below the initial string and likewise isolated with surface casing that is cemented in place. As each successive section of the well is drilled, the diameter of the wellbore is reduced from the previous section of the well causing a typical well structure to resemble a multistage telescope. In order to reach the subterranean reservoir with an adequate hole diameter to facilitate the tools required to drill through hard formations found at these great depths, the diameter of the initial hole sections and casing strings used to isolate the typical initial hole sections can be within a range from about 30 inches to about 48 inches in diameter.
The tubular members used to isolate these large diameter hole sections typically contain plain end line pipes that have had a male threaded connection welded on one end of the tubular section and a female threaded connection welded on the other end. To form a continuous tubular string, these ends can be connected together, such as end-to-end by these threaded connections, with a male “pin” member of a first tubular member configured to engage the threads of a corresponding female “box” member of a second tubular member. Alternatively, a casing string can be made-up of a series of male-male ended casing joints coupled together by female-female couplers. The process by which the threaded connections are assembled is referred as “making-up” a threaded connection, and the process by which the connections are disassembled is referred as “breaking-out” the threaded connection. Individual pieces (or “joints”) of oilfield tubular members may come in a variety of weights, diameters, configurations, materials, and lengths.
Generally speaking, small diameter casings have the threaded connections machined directly onto the pipe body and large diameter casings usually have threaded connections that are welded on. The welded connections that can be welded on to large diameter casings are commercially available in many different types of connectors including several types that incorporate multi-start threads. The use of a multi-start thread results in a connector design that requires only a portion of a full rotation of the pin into the box from stab in to full make-up of the threaded connection as opposed to a single start threaded connection that requires several rotations to make up the pin connection fully into the box connection. Most of the multi-start connection types require a range from 90 degrees of rotation up to 180 degrees of rotation in order to make-up a threaded joint between the two pipes.
The typical tools used to make-up threaded joints into contiguous strings are the power tongs and manual tongs. Power tongs are mechanized pipe wrenches that incorporate gear drive systems capable of rotating on a continuous basis by a central rotary gear which houses the pipe gripping elements. Regardless of whether a connection requires 3, 6, 10, or more full rotations of one joint relative to the other joint, the power tong is capable of providing continuous rotation. The power tong is capable of delivering very high torque required to generate a seal tight connection between the male threaded connection and the female threaded connection. Power tongs are available in various makes and models and can accommodate gripping tubular members ranging in outer diameter from as small as about 2⅞ inches to 20 inches. In order to accommodate gripping tubular members having outer diameters of greater than 20 inches, a power tong would have to be a very large piece of machinery that is quite heavy to manipulate on the rig floor and expensive to manufacture.
An alternative to a power tong that is in wide spread use for making-up tubular strings with large diameter casings is the use of two manual tongs. One manual tong can be secured to the lower joint that is suspended in the wellbore and snubbed off via a cable to a structure on the rig floor to prevent rotation of the string. The second manual tong can be secured to the upper “add-on” joint and attached to a winch line. The line can be used to pull the handle of the manual tong causing the add-on joint, gripped by the second manual tong, to rotate relative to the string, thereby making-up the threaded connection between the add-on joint and the string. Each pull of the handle of a manual tong can result in about 30 degrees to about 45 degrees of rotation of the upper joint into the string. In order to fully make-up a connection that requires 90 degrees rotation from stab in to full make-up with this alternative two to three pulls of the manual tong are required. There may be safety issues with the use of manual tongs, and in addition, such use of manual tongs is a time-consuming process.